Re: [PATCH] Lazy FPU save/restore

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Anthony Liguori wrote:
>>
>> ... and reverted.
>>
>> Running an fpu load on both guest and host shows corruption (both on 
>> the guest and host).  The load is
>>
>>
>>> #include <stdio.h>
>>>
>>> void test_fpu()
>>> {
>>>     int i;
>>>     double f = 0;
>>>
>>>     for (i = 0; i < 10000000; ++i)
>>>     f += 1 / (1.0 + i);
>>>     printf("%20.16f\n", f);
>>> }
>>>
>>> int main(int ac, char **av)
>>> {
>>>     while (1)
>>>     test_fpu();
>>> }
>>
>> Compiled statically with -O2 on 64-bit.  I don't know what's wrong -- 
>> the code looks correct (well, on Intel it wants KVM_GUEST_CR0_MASK to 
>> include CR0_MP_MASK and CR0_TS_MASK, but it fails with that too, and 
>> it fails on AMD as well).
>
> I'll have to try and setup a 64 bit system.  I cannot reproduce on my 
> 32bit system with your test program.

It may be related to 64-bit (as that uses sse for floating point), or to 
the fact that I use ssh on a remote host, which causes more context 
switches.  I'll try to reproduce on 32 bits with my setup.

-- 
error compiling committee.c: too many arguments to function


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